1. Field of the Invention
This invention relates to a high voltage current transformer and, more particularly, to such a transformer having clamping means for a self-contained unit with two oil systems.
2. Description of the Prior Art
The primary winding of high voltage current transformers operates at a high voltage to ground, with a low voltage drop across its terminals. Generally, current transformers of prior construction having employed various types of mounting means. For example, in U.S. Pat. No. 2,849,694, a pair of elongated bushing cores are mounted to extend throughout their lengths in closely-spaced, substantially-parallel relationship. The conductive studs of the bushing cores are suspended from the top of the ceramic shell, and they extend downwardly into a tank assembly. A single oil system insulates and cools the current transformer. In U.S. Pat. No. 2,549,426, a primary conductor is contained within a rigid insulating tube which is supported by spaced gasketed rings at the upper and lower ends of a porcelain shell. Again, a single oil insulating and cooling system is used.
Moreover, some current transformers of prior-art construction embodied the so-called "eye-bolt" or "U-shaped" type of primary winding as disclosed in U.S. Pat. Nos. 2,804,577 and 4,052,685. These constructions consist of sharp-turned primary winding structures that require non-automated, labor-intensive, hand-wrapped paper insulation. Many of such transformers have also included tie-rod or cemented joints between porcelain bushings and adjacent parts that were rigid assemblies rather than flexible and, therefore, not resistant to exceptional seismic activities.